1. Field of the Invention
The present invention is directed to an apparatus method for providing a constant non-invasive monitoring of an infant's body temperature in its crib. It also is able to detect changes in the temperature and if such changes exceed a predetermined, selected range, sound an alarm to attending personnel. The device of the invention also provides a means of continuously tracking and recording an infant's temperature at predetermined time intervals.
In the pediatric care environment it is usually essential that a sick infant's temperature be closely monitored and that any significant changes in the temperature be detected as soon as possible. Such changes of temperature often indicate a critical shift in the patient's condition. Effective monitoring of temperature changes requires labor intensive activity measuring the temperature by conventional and invasive means which often disturb and irritate the pediatric patient, interfering with much needed rest and sleep. In addition, the thermometers often are subject to significant instrumentation error.
Recent developments have provided less invasive means of measuring infant and other patient temperatures that are determined by simple external contact means. Even with these devises however, instrument error is still a significant factor. Furthermore, the contact is still disturbing to the pediatric patient even when less invasive instrument means are utilized.
Recently, there have been instruments developed capable of measuring the surface temperature of objects and of human beings by utilization of infrared energy, often in a form of an infrared device or gun that is aimed at the surface of the subject.
These devices have been subject to error in the cases where the infrared beam contacts background surfaces which interfere with the accurate reading of the target surface temperature desired to be measured. Such errors have been minimized by providing the infrared temperature transducer with a pulse setting light beam to target the area to be measured, giving a positive indication of the orientation of the infrared energy being utilized and the temperature measurement operation.
Instrumentation theory and practice teach that all instruments, in order to measure a quantity, must either consume or divert a small portion of that quantity in the process of measurement. This act disturbs the original quantity, altering its magnitude, and since it is the altered magnitude that is actually measured, an erroneous reading results.
This error-producing process applies to all known temperature measuring instruments except infrared thermometers. All conventional thermometers require a probe to touch the object being measured, which is usually at a different temperature. Consequently heat transfer occurs between the probe and the object until equilibrium occurs. After equilibrium occurs, the temperature measurement is said to have "come up," but the object is now either colder or warmer than it was before the probe "invaded" it. The amount by which the object is cooler or warmer than the probe is a part of the error of measurement.
Infrared thermometers produce no "invasive error." A hot object "target" is radiating its infrared radiation in all directions whether or not the infrared thermometer is there taking its temperature. The object's radiation characteristics, and hence its temperature, are not disturbed by the presence of the infrared thermometer.
The purpose of the present invention is to provide a patient, especially a pediatric patient, temperature monitoring alarm system which is completely noninvasive and does not require manual operation by medical personnel attending the patient. Means are provided for temperature monitoring or detecting and the device automatically follows an infant which is a moving target, unrestricted in its crib or other sleeping area.
This is accomplished by providing an infrared temperature detecting transducer mounted above the infant's sleeping area. The device is mounted on a pan/tilt mechanism that allows the temperature monitoring transducer to stay focused on the portion of the body of the infant which is particularly intended to measure the surface temperature thereof; i.e. forehead, back, etc. even as the infant moves about the crib. Electronic means are provided to record the temperature at predetermined times and also to signal an alarm when a sudden rise or fall in temperature is detected and/or when the surface temperature rises or falls to a predetermined absolute level.
2. Prior Art
Infrared temperature transducers of the type utilized in the present apparatus are commercially available from Everest Interscience, Inc.
U.S. Pat. No. 4,738,266, Thatcher discloses a utilization of infrared detectors and radiators mounted on a pediatric crib to detect apnea. In this case, the absence of infant breathing and the exhaling of carbon dioxide which absorbs infrared radiation is utilized to detect a sudden cessation of breathing on the part of the pediatric patient, we associate with S.I.D. (sudden infant death syndrome). Thus, when a rise in the infrared energy present is detected, an alarm is sounded to indicate a decrease or cessation in the amount of carbon dioxide exhaled by the infant.
A similar earlier system is shown on U.S. Pat. No. 4,350,166, Mobarry. None of these devices measure temperature nor do they track or scan a target surface around the specified crib area. They monitor the whole area.
Pan/tilt mechanisms for security video cameras are well known in the prior art are adapted herein for scanning the intended target with an infrared transducer.